The present invention relates to a method and apparatus for forming subterranean concrete piles.
It has been proposed to form subterranean concrete piles by driving a casing tube, by means of impacts, into the ground either by the displacement method, in which a pointed nose cone is applied to the casing tube to divert soil from the space to be occupied by the tube, or by the bored casing method, in which the casing is bored into the ground and the soil contained within the casing is subsequently removed. The disadvantages of these methods are that the casing tube has a smooth exterior, and also substantial headroom must be available to enable the casing to be driven into the ground.